Heart disease affects the lives of thousands of persons each year in the United States. And, as the U.S. population ages, the annual number of heart disease-related deaths is expected to grow. A percentage of these deaths can be postponed or eliminated if diagnosed and treated early. Furthermore, early diagnosis and treatment often improves the quality of life for afflicted individuals as well as reduce the overall cost of treatment because usage of acute care facilities, such as operating rooms, intensive care units, and rehabilitation facilities, is reduced or eliminated.
One common heart abnormality is caused by insufficient blood supply to portions of the heart muscle (myocardium). This abnormality may be referred to as focal wall abnormality (WMA), and is characterized by dysynchronous contraction of the left ventricle of the heart. WMAs decrease the overall performance of the left ventricle and correspondingly increase the workload on the heart, which may lead to premature heart failure.
If properly diagnosed, patients suffering from WMA may be treated using cardiac resynchronization therapy (CRT) for restoring synchronous contraction of the interventricular septum and the left ventricular free wall. CRT is achieved through the use of a pacemaker capable of biventricular pacing. However, before CRT can be undertaken, a proper diagnosis must be made which includes detection of WMA and determination of the proper settings for encoding into the pacemaker. Quantitative measurements are desired for efficient and accurate diagnosis of WMA. Accurate identification of the ventricular borders is useful for determining the volume of the left ventricle and for determining the ejection fraction (EF) which refers to the portion of blood that is pumped out of the filled ventricle as a result of a heart beat. Accurate identification of ventricular borders also makes possible generation of time-volume curves so a diagnostician does not have to rely on estimates of left ventricular volumes.
Identification of ventricular borders is problematic using prior art techniques because they require highly trained diagnosticians for reliable interpretation of heart data. In addition, prior art techniques do not produce quantitative analyses for detection, tracing and display of heart data.
What is needed is a method and apparatus for making on-line quantitative analyses of moving tissue and in particular of heart data, such as cardiac function and ventricular wall motion for facilitating the detection, tracking and display of information about cardiac size, morphology and function for routine clinical use.